Dolly The Sheep: Somatic Cell Nuclear Transfer

Unlike some movies, cloning in real life doesn’t produce a full grown exact replica of someone. A type of cloning that occurs naturally is when identical twins are born (“What Is Cloning?”). Somatic cell nuclear transfer (SCNT) is a type of cloning that has to be done in a lab. In SCNT they take the nucleolus out of an egg cell, replace it with the nucleolus of a somatic cell (body cell with two complete sets of chromosomes), and make the egg cell divide into a blastocyst (“What Is Cloning?”).

When the mRNA has been targeted, a double-stranded RNA (dsRNA) interferes with the disrupted micro RNA which stops it from creating a new protein (3). This method does not completely block protein production but there are still residual amounts of protein produced, however in Daisy the cow, the protein for BLG was no longer detected in her milk. Daisy the cow was cloned by a technique called the somatic cell nuclear transfer (SCNT). This means that a somatic cell, or body cell, was taken from the original parent, in this case an ear skin cell from a high-merit cow named Aspen (4), and cultured in a low nutrient state. It then becomes dormant, where the nutrients are keeping the cell alive but it no longer undergoes cell replication. The nucleus of the dormant cell is now removed and is inserted into an enucleated oocyte (egg) cell, which is the reproductive cell of a donor cow. Enucleated means that the nucleus of this reproductive cell has been removed in order for the new one to be infused in it. The dormant somatic cell and the reproductive cell are then shocked with an electrical pulse which sends a surge of energy which allows them to fuse into one

Reproductive cloning is similar to IVF because it also brings embryo into existence. This potential infertility treatment involves the creation of embryo using the genetic material of the parent. This is done by extracting nucleus from the person’s somatic cell and transfer into an oocyte through somatic cell nuclear transfer. Thus, the processed oocyte

Therapeutic cloning, what is it? Some might think it involves the cloning of a human being. In actuality, it refers to the removal of a nucleus, which contains the genetic material, from virtually any cell of the body and its transfer by injection into an egg (acquired from female) that is not fertilized and from which the nucleus has been removed. Therapeutic cloning can also be referred to somatic cell nuclear transfer (SCNT). To perform SCNT researchers extract the nucleus from the egg, the nucleus stores all the genetic information for any living subject. Then researches take a somatic cell, which is any type of cell that is not a gamete, and extract its nucleus from the cell.

that goes into creating a clone. First, scientist remove a somatic cell from an animal that they

Scamper won a record 10 Professional Rodeo Cowboys Association world championships from 1984-93 and helped make James the first million-dollar cowgirl and the all-time leading money winner in barrel racing. Scamper is the only barrel racing horse in the Pro Rodeo Hall of Fame. Scamper was a plain bay gelding picked out of Charmayne’s father’s pen of colts by herself, proving to the world that Scamper was no ordinary horse. The fact that he did not have the fancy breeding as many of the other competitive barrel horses set him apart from all the rest of the horses at that time. Making him a perfect candidate to be a part of the new cloning program. Although Scamper was a very important breakthrough in the cloning of animals, he was not the first. The first mammal to be intentionally cloned from an adult cell was a sheep called Dolly in 1996. Dolly was created using the technique of somatic cell nuclear transfer. The nucleus is the part of the cell that stores genetic material. To produce Dolly, scientists used an udder cell from a six-year-old Finn Dorset white sheep. They had not found a way to 'reprogram' the udder cells - to keep them alive but stop them growing – which they achieved by changing the growth medium. Then they injected the cell into an unfertilized egg cell which had had its nucleus removed, and made the cells fuse by using electrical pulses. The unfertilized egg cell came from a Scottish Blackface ewe that dolly was used to be born. When they finally had managed to fuse the nucleus from the adult white sheep cell with the egg cell from the black-faced sheep, they needed to make sure that the final cell would develop into an embryo. They cultured it for six or seven days to see if it would be divided and developed normally, before implanting it into a surrogate mother, another Scottish Blackface ewe. Even though Dolly had a

The first being a female gamete, known as the ovum (egg/oocyte) and the second being a somatic cell, referring to the cells of the human body. Skin cells, fat cells, and liver cells are a few examples of somatic cells. The nucleus of the donor egg cell is sucked out through a micropipette and discarded, leaving a recipient egg with no nucleus, but an intact cytoplasm and the cellular machinery for producing an embryo. Next a donor somatic cell containing the genetically manipulated DNA, is taken from the cow with lack of BLG protein in its milk, and is cultured in a low nutrient medium which deprives the cell from nutrients so it becomes dormant. The cell stops dividing and switches off its active genes. The two cells are placed next to each other and an electrical pulse causes them to fuse together, the somatic cell nucleus is reprogrammed by its host egg cell. A time delay improves this process by allowing unknown factors in the cytoplasm to activate the chromatin. Cell division is then triggered by a second electric pulse engaging cellular activity and effectively jump starting the cell into the production of an embryo. After almost a week, the egg is implanted into the uterus of a surrogate mother. The egg is now viable and capable of producing an adult organism containing all the necessary genetic information from just one parent. This results in the original genetically engineered cow successfully producing Daisy, the cloned cow with genetically modified DNA leading to the production of milk lacking in the BLG

Dolly the sheep, a clone born in Scotland in 1996, was the first mammal to ever be cloned from an adult cell using nuclear transfer. Her birth demonstrated for the first time that even DNA from already specialised adult cells could be used to create an entire healthy organism.

hen people think of the word “cloning” they often have in mind frightening images of duplicates of humans in a kind of mad scientist experiment. In fact, many people were outraged when Dolly came as a result of a cloning experiment in Scotland (Brown, 2009). Therapeutic cloning, however, is completely different and does not involve the creation of a perfect copy from another human being. In therapeutic cloning, fertilization of sperm or eggs is not implanted into the uterus to create a child. Therapeutic cloning is a phase of a procedure known as somatic cell transfer (SCNT) In this procedure; scientists take a somatic cell from the nucleus of an egg (the nucleus contains genetic material) and then it is transplanted. In practical applications

Somatic Cell Nuclear Transfer is the process of creating a cell, organ, or organism by using an egg cell from one donor and a body cell from another donor. It is used in therapeutic cloning, which is the creation of a healthy body cell to replace a faulty cell, allowing for patient-specific treatments. SCNT can also be used in reproductive cloning, which is used to clone full animals or possibly humans. The process of SCNT is completed by taking an egg cell from a female donor, and a body cell, any body cell, from another donor. The nucleus is removed from the egg cell, while the nucleus from the body cell is implanted into the egg cell as a replacement. The cell begins to divide, and eventually grows into a developed organism with the same

They took a cell from an adult sheep’s udder and extracted the DNA. It was then put into a “blank” cell. This was the first time an adult cell had been used instead of an embryo cell. Adult cells do not have as much DNA as embryo cells. After 277 attempts an embryo was finally produced. Six days later the cells were transferred into a surrogate mother. The pregnancy progressed like normal and Dolly, named after singer Dolly Parton, was born on July 5th, 1996. Dolly lived for six years, which is only half the lifespan of a normal sheep. Dolly even had lambs. This first cloning led to many discussions about the morals of cloning. Animals cloned can have various health defects. The discussion even was presented that if humans were cloned they would lack personality and emotions. While humans haven’t been cloned great gains have been

Reproductive cloning consists of producing a “later born twin” of the early embryo. It is taken from an adult DNA cell and transplanted into a human egg, replacing the nucleus. This procedure is referred to as Somatic Egg Cell Nuclear Transfer. Once ready, the embryo is then placed into the uterus of a woman which then proceeds onto birth. In contrast to this form, adult stem cell cloning is when the cell can clone and make copies of itself in order to help fight off diseases such as Parkinson’s or Heart disease. Somatic cell transfer is used again by planting a human egg in place of the nucleus. However, in therapeutic cloning, the egg cells only survive for up to fourteen days which then give scientists the opportunity to remove the trophoblasts once more and take out the contents inside the embryo and use them for further experimentation. Therefore, as a conclusion to this point, reproductive cloning and therapeutic cloning both involve the destruction of an embryo for research or treatment which do not need to be contemplated because of different alternatives to destroying an embryo (Hallowell).

On February 24, 1997 history was made. The first cloned adult mammal was born through somatic cell nuclear transfer (McCuen, 11). Somatic cell nuclear transfer is when a nucleus of a mammary gland is removed and fused with an egg by using electrical pulses. The pulses prompt the egg to divide to form an embryo. The embryo is then transferred to a uterus where it is implanted to grow (McCuen, 10). Before the creation of Dolly, many scientists were unsuccessful in their attempts to produce a genetically identical copy of a cell. In the rare occasion that they were successful in their attempts, they would soon be discouraged due to the inability of the clone to sustain life. It took hundreds of attempts before Dolly’s team of scientist could obtain a successfully cloned sheep. Of the 277 successful transfers, only 29 became embryos. And of these 29 embryos, Dolly was the sole survivor (Sweat, 1). What sets Dolly apart from previous clones is the fact that she was cloned differently. Dolly was cloned not from sex cells but from mature mammal cells with no reproductive function (Sweat, 1). Even though Dolly was a

The nucleus of a somatic cell is extracted and is placed in the enucleated egg

The steps taken in the process of SCNT cloning are: the nucleus, which contains the organism's DNA, of a somatic cell is removed from a healthy egg after it has reached its dormant stage ( where cell replication no longer occurs) and the rest of the cell is discarded. It is necessary for the cell to be in dormant stage as dormant cells can stay in this state for long period of time, for this time period the cell is inactive. At the same time, the nucleus of an egg cell is removed from another cow. The nucleus of the somatic cell is then inserted into the enucleated egg cell.